If he wants to go to university then remind him that it rarely matter what he studies (unless he has a specific career in mind), which enables him to study something he enjoys. He doesn't have to do "law" or "medicine" or "journalism" or "social work" to have great career opportunities - in facts many more doors are opened by a broad degree. Biochemistry, biomedical science, maths, geography, geography with a year abroad (highly competitive courses), even a combination like biology and geography are all very strong options. With biology, chemistry, and maths he'd be well set up for natural sciences too at certain universities (Lancaster/Cambridge/York to name a few). With a degree in one of those subjects he wouldn't have to worry about a specific future career - just know that he'd be competitive for many options.
While jobs in research are low paid they're often quite rewarding for those who really love sciences, then from a maths/science/geography degree there are options for roles in forensics, healthcare (like a healthcare scientist), microbiology, toxicology, engineering, statistics, a lab manager/scientist, a dietician, botanist, zoologist, cartographer, environmental consultant, surveyor, town planner, aid/development worker, landscaping, tourism, transport, sustainability, science writing. With a broad degree he would also be able to go into IT/finance/business/logistics etc... so many options! He doesn't need a specific idea just yet.